Our world is noisy. The reverberations of buzzing traffic, multisonous concerts or the chatter of conversations compose background noise. Individuals suffering hearing impairments, unlike those having normal hearing, are unable to suppress these sounds. The audible components of this interference mix too strongly with the foreground, thereby impeding the localization and segregation of the sound sources. Thus, our world, with its complex soundscapes, becomes very difficult to comprehend for the hearing impaired.
In an attempt to aid the hearing impaired, the technology concept of Assistive Listening Devices (ALD) is known. Such ALD amplification instruments are designed to be helpful in specific listening situations. For instance, specific ALDs are available that are used to amplify the TV, the telephone, sound in theaters, churches and public speakers. Typically, an ALD includes a microphone, amplifier and loudspeaker. Unlike a hearing aid, the microphone is typically located remotely from the body of the ALD device and placed near the sound source to enable the pickup of the desired sound, while minimizing noise.
Efforts have been made to enhance the speech signal in cellular telephone handsets. For example, currently on handsets incorporating iDEN technology, available from Motorola, Inc, of Schaumburg, Ill., when the handset is in an active service call, the background noise is suppressed to allow the second party to clearly hear the iDEN user. However, if the other user is in a very noisy environment, the iDEN user would still hear the background noise along with the foreground signal. Thus, because of these reasons and others, cellular telephones have been characterized as a communication device, but not as an ALD.